1. Field of the Invention
The present invention relates to an optical disc, and more particularly, to an optical disc on which data can be recorded quickly and on which an exclusive region for a specified purpose can be selectively allocated at the outer circumference thereof, and a method of and an apparatus for recording data thereon.
2. Description of Related Art
Optical discs are used as data storage media of optical pickup devices for recording and reproducing data without contact. Two types of optical discs are compact discs (CDs) and digital versatile discs (DVDs), which differ according to recording capacity. Some are recordable, such as the 650 MB CD-R, 650 MB CD-RW, 4.7 GB DVD+R/RW, 4.7 GB DVD-RAM, and DVD-R/RW. Others are read-only, such as the 650 MB CD and 4.7 GB DVD-ROM. Furthermore, a next generation DVD whose recording capacity is over 15 GB is under development.
Presently, the only type of conventional recordable DVD is a 4.7 GB single layer disc. However, DVD-ROMs are available in 8.5 GB dual layer discs. In order to backup these 8.5 GB discs, an 8.5 GB recordable DVD is required. However, in this case, the recording time roughly doubles, which can be a disadvantage for the user. Although the recording speed can theoretically be improved, this would require improvements in disc technology and therefore, a method of effectively recording data at a conventional speed is required to immediately introduce the 8.5 GB recordable DVD to the market.
FIG. 1A illustrates the structure of a conventional rewritable optical disc. FIG. 1B illustrates the structure of a conventional read-only optical disc. The structure of a lead-out area of the rewritable optical disc shown in FIG. 1A is almost the same as the structure of a lead-in area.
FIGS. 2A and 2B illustrate conventional methods of recording data on a dual recording layer disc. FIG. 2A shows the case where the recording direction is an opposite track path (OTP), and FIG. 2B shows the case where the recording direction is a parallel track path (PTP).
As shown in FIGS. 2A and 2B, user data is recorded on a recording layer L1, and then the remaining user data is recorded on a recording layer L2. Pattern data having a lead-out attribute is recorded on an area on which the user data cannot be recorded, in the recording layer L2. Commonly, the area connecting data storage layers to each other is called a connecting area, to discriminate from the lead-out area and the lead-in area. The recording methods shown in FIGS. 2A and 2B can be applied to read-only and rewritable discs.
FIGS. 3A and 3B illustrate other conventional methods of recording data on a dual recording layer disc. FIG. 3A shows the case where the recording direction is an opposite track path (OTP), and FIG. 3B shows the case where the recording direction is a parallel track path (PTP). As shown in FIGS. 3A and 3B, if the total amount of data to be recorded is less than the total capacity of the two recording layers L1 and L2, then in order to record the same amount of data on each of the two recording layers L1 and L2, data is recorded up to a specified position before the lead-out area on each recording layer, and pattern data having the lead-out attribute is recorded on the remaining area. In particular, the pattern data having the lead-out attribute is recorded out to the outermost circumference of the disc.
FIGS. 4A and 4B illustrate other conventional methods of recording data on a dual recording layer disc. FIG. 4A shows the case where the recording direction is the OTP, and FIG. 4B shows the case where the recording direction is the PTP. Like the recording methods shown in FIGS. 3A and 3B, the data recording methods shown in FIGS. 4A and 4B show the case where data is recorded up to a specified position before the lead-out area on each recording layer in order to record the same amount of data on each of the two recording layers L1 and L2, and pattern data having the lead-out attribute is recorded on the remaining area, when the total amount of data to be recorded is less than the total capacity of the two recording layers L1 and L2. However, unlike the recording methods shown in FIGS. 3A and 3B which record the pattern data having the lead-out attribute out to the outermost circumference of the disc, the data recording methods shown in FIGS. 4A and 4B record data only as far as necessary, and do not record the data out to the outermost circumference of the disc.
According to the conventional data recording methods described above, additional data recording time is required to record the pattern data having the lead-out attribute on the area on which user data cannot be recorded.
In the case of a recordable optical disc, a test area to record data for testing is allocated to the optical disc in order to record actual data at an optimum recording power before the actual data is recorded on the optical disc. However, in the case of an optical disc having a plurality of recording layers, since recording characteristics vary according to which recording layer data is recorded on first, the test area must be allocated considering the recording characteristics when the test area for an optimum power control (OPC) is allocated to the optical disc. In particular, when the test area is allocated to the outer circumference area of the optical disc, the characteristics of the outer circumference area must be considered. Also, the process is complicated by the fact that in an optical disc having a plurality of recording layers, the recording characteristics of the outer circumference area are worse than in an optical disc having a single recording layer. Furthermore, when the test area and an area having another purpose are allocated to the outer circumference area of the optical disc, the characteristics of the outer circumference area must also be considered.